b Standard deviation b
Calculating standard deviation:
1. find
the mean or average of the group of numbers
-to find the mean
add the numbers together and divide by how many total numbers there are.
2. find
how much each number deviates from the average
-deviates
(absolute value of the first number minus the
average number)
3. then
take the new set of numbers and square each one to
find again a new
set of numbers
4. now
find the mean or average of the newest numbers which
is the numbers
squared that you found in #3
5. take
the square root of the mean of square numbers……this
is your standard
deviation.
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example 1.
Calculate
the standard deviation for the numbers: 14, 16, 19, 17, 15
16 .2^2 = .04
19
81/
5= 16.2 2.8^2 =
7.84
17 .8^2 = .64
+ 15
1.2^2
= 1.44
81
2.
find deviation: |14 - 16.2| = 2.2
4. find mean of square numbers:
|16 - 16.2| = .2 4.84
|19 - 16.2| = 2.8 .04
|17 - 16.2| =
.8
7.84 14.8/ 5 = 2.96
|15 - 16.2| = 1.2 .64
+
1.44
14.8
5.take the square root of 2.96
sqrt
2.96 = 1.74
1.74 is
your square deviation